.book_id {
    position: relative;
    text-align: center;
    height: 80px;
    margin-top: 10%;
    background-color: #b7dccf;
  }
  .book_id input {
    text-align: center;
    margin-top: 25px;
    width: 280px;
    height: 30px;
    font-size: 17px;
  }
  .button {
    text-align: center;
    margin-top: 7%;
    font-size: 20px;
  }
  
  .button button {
    width: 120px;
    height: 35px;
    background-color: #eee;
    border: none;
    padding: 5px 10px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 17px;
  }
  
  .button button:hover {
    background-color: #cfd8dc;
    color: #af6967;
  }
  
  .button button:disabled {
    background-color: #eee;
    color: #aaa;
    cursor: auto;
  }
  .tip {
    position: relative;
    text-align: center;
    margin-top: 1%;
    color: red;
  }
  